The present invention is directed to an apparatus for selectively introducing or "blowing in" one or more different weft threads or yarns in an air jet weaving loom. During the weaving of patterns, it is often desirable or necessary to change the color or type of weft yarn being introduced through the weaving compartment. In previously known devices, each of such different types or colors of yarn has been introduced to the weaving compartment through a separate nozzle. The several nozzles are so mounted that the nozzle containing the selected yarn is mechanically moved into the proper position for introducing the yarn into the reed tunnel, which is formed by the U-shaped cross-sectional area of the reeds and extends through the weaving compartment or warp shed. Upon completion of use of the selected yarn, the corresponding nozzle must then be moved out of registration with the reed tunnel and another nozzle moved thereinto. Examples of such apparatuses are described in West German Offenlegungsschrift (publication) No. 3014776 published Nov. 6, 1980, and a Netherlands Octrooiaanvrage No. 7100266 published July 11, 1972. As air jet weaving looms operate at extremely high speeds (four to five hundred picks per minute), it is necessary that the change from one weft yarn to another occur as rapidly as possible. Toward this end, if a mechanical translation of the nozzle is required to effect change of the weft yarn, it can be easily seen that this is disadvantageous since it is time consuming. One improvement already suggested in the earlier mentioned German publication is to mount the individual nozzles with the exhaust openings lying close to one another around a fixed pivot point. This still requires mechanical movement, however, and the additional support parts and timing devices are difficult to accomplish and very expensive.
The present invention, on the other hand, is directed to a unique nozzle construction for selectively introducing one or more weft yarns in air jet looms, which nozzle overcomes the problems set forth above and eliminates all mechanical movement of nozzles. According to the invention, the problem is solved by an apparatus which includes a single, main, stationary nozzle fed by a plurality of introductory or "blow in" nozzles which are mounted in and selectively feed a weft yarn into the main nozzle from which it is transported through the weaving compartment. The nozzle according to the present invention minimizes the moving parts necessary to effect this result. Other than the movement of a breaking or yarn reverse device, there is no movement required. In other words, the movement of one yarn into and out of operative communication with the main nozzle can be made quickly with no mechanical movement of the nozzles. The apparatus according to the present invention can be positioned immediately adjacent the rider beam or may be spaced therefrom as desired.
In summary, the apparatus according to the present invention provides a stationary main nozzle through which one or more of a plurality of yarns are selectively introduced to the weaving compartment. In the main nozzle, the selected thread is guided through an orifice in the central body thereof. Each yarn is introduced through its own stationary introductory nozzle and through an auxiliary orifice to the main nozzle orifice from whence the main air jet blows the yarn through the weaving compartment. When the yarn is to be taken out of operation, it is cut, and a reversing or braking mechanism pulls the yarn back up into the auxiliary orifice from operative engagement with the main nozzle, so that another selected yarn may be introduced thereinto. Further advantages and characteristics will become apparent from reading the following detailed description of the preferred embodiment along with the accompanying drawings in which: